The power consumption of recent semiconductor integrated circuits tends to increase more than ever due to their high functionalities. For example, recent display panel drivers suffer from a significant increase in the power consumption due to an increase in the number of pixels of display panels. Power consumption reduction is one of the most important issues of recent semiconductor integrated circuits.
It is known in the art that, although a semiconductor integrated circuit consumes power in various ways, a considerable percentage of the power consumption in a semiconductor integrated circuit is caused by switching the voltage levels on signal lines.
When binary data are transferred over a set of signal lines, the signal lines are repeatedly pulled up to the “high” level and pulled down to the “low” level. In this operation, the signal lines are repeatedly charged and discharged, and this causes considerable power consumption.
One known technique for reducing the power consumption caused by switching the voltage levels on the signal lines in transferring binary data is to transmit a bit-inverted data of a binary data of interest (that is, data obtained by bit-inversion of the bits of the binary data of interest), when more than half of the bits of the binary data to be currently transmitted are inverted from the corresponding bits of the previously-transferred binary data. Such technique is disclosed, for example, in Japanese Patent Application Publications Nos. H08-314589 A and 2009-9289 A.
However, there is room for further reducing the power consumption, when the above-described technique is used in transferring compressed image data.